Some help please

Hey gents.
All right, so I went on an hour long ride yesterday and when I got to the final stretch of the ride my motor stopped working. When I put the choke on it runs (it turns over and stays on as long as i give it a little gas) but as soon as I take off the choke it sputters out. I took out the carb and inspected it and put it back in snug. I tightened the intake and still the same problem. It's also been leaking a bit of oil. I'm gonna take out the exhaust and try to clean it but any suggestions as to why this may be happening would be great.

I have a regular china girl setup with a speed carb.

Can you elaborate Venice? What does the main jet look like? And what do you mean put the filter in-line ddesens. Pardon my ignorance, I'm still learning.

I took apart the carb and the piece the needle goes into was unscrewed. I put it back in place. That should do it. Thanks gentlemen.